I don't think so because a) Maggie b) Harry was not really dead. That has been discussed as nauseam, but he would have broken the "die alone" curse if he was truly dead.
And about literal, yes, I think it meant literal blood. A foster child would not have had the same effect, for instance, no matter how much loved they were. But as there is no clear indication in the text, your opinion and mine are equally worthy.